THE FIRST STAGE OF RISK ASSESSMENT IN A PROCESS
PLANT ESSENTIALLY CONSISTS OF THREE STEPS: 2. IDENTIFYING THE HAZARD 3. ESTIMATING THE EFFECTS OR CONSEQUENCES OF THE HAZARD 4. DETERMINING PROBABILITY OR LIKELIHOOD OF OCCURRENCE OF HAZARDOUS EVENT

THE NEXT STEP OF RISK ASSESSMENT
TO DETERMINE WHETHER EFFECTS OF THE CONSEQUENCE AND THE PROBABAILITY OF OCCURRENCE OF THE HAZARD IS WITHIN THE ACCEPTABLE LIMIT OR NOT.

COMMONLY USED STRUCTURED HAZARD IDENTIFICATION TECHNIQUES
• WHAT IF ? ANALYSIS:
• • • • • • What if the Raw Material contains impurities? What if Cooling Water is Lost? What if the Vessel Agitation Stops? What if Power Supply Fails? What if the Temp./ Press. Sensor Fail? What if the Pump Stops? etc.

1. HAZOP STUDY
GUIDE WORDS • NO • MORE • LESS • AS WELL AS • PART OF • REVERSE • OTHER THAN, etc.

3. FAILURE MODE AND EFFECTS ANALYSIS (FMEA)
FMEA evaluates the ways in which an Equipment can Fail and the Effects of such Failures on an Installation

4. FAULT TREE ANALYSIS (FTA)
Deductive Reasoning Process

5. EVENT TREE ANALYSIS (ETA)
Inductive Process

RISK ACCEPTABILITY CRITERIA
Statistical Experience Shows
•Chance of Death due to Risk of Driving, Flying or Smoking is 1 in 100000 or 10 –5 •Chance of Death from Lightning or Falling of Aircraft is around 10 –7 or 1 in 10000000 It is therefore generally accepted that the Risk of Death 1 in 100000 or 10 –5 per Year is Alarming. Action needs to be taken to Reduce the Risk BELOW the level 1 in 1000000 or 10 –6 per Year and it is generally accepted without concern for Industrial People.

try to eliminate Risk in Business Enterprises is Futile”. “Risk is inherent to the commitment of present resources to future expectations”. Indeed, economic progress can be defined as the ability to take greater RISKS. Even the attempt to minimise them, can only make them irrational and unbearable.